Add weight and bias functions to LayerNorm (#1306)

candle-nn/src/layer_norm.rs

@@ -95,6 +95,14 @@ impl LayerNorm {
             eps,
         }
     }
+
+    pub fn weight(&self) -> &Tensor {
+        &self.weight
+    }
+
+    pub fn bias(&self) -> Option<&Tensor> {
+        self.bias.as_ref()
+    }
 }
 
 impl crate::Module for LayerNorm {